GB1064983A - A remote controlled safety device for igniting gas apparatus - Google Patents

Abstract

1,064,983. Controlling gas burners. JUNKERS & CO. G.m.b.H. Sept. 24, 1963 [Oct. 6, 1962], No. 37434/63. Heading F4T. A safety control device for a gas burner 10 comprises a cam 20 actuating a rocker 31 adapted to open a pilot valve 21 and a main valve 36 against the action of their springs (not shown), electric contacts 24, 28 actuated by the cam for energizing an electric igniter and an electric motor driving the cam and an electromagnet 54 adapted to hold the pilot valve 21 open when energized by a thermoelement 13 heated by the pilot burner 11. The rocker 31 has a circular bore or an elongated slot 37 by means of which it is pivoted to an eccentric pin 30 on the cam. The ends of the rocker arm are slotted to embrace pivotally the stems 33, 35 of the pilot and main valves 21, 36. In operation, when a remote manual switch 14 and a room thermostat 61 are closed a relay 62 closes to complete the circuit of the electromagnet 54 and the thermo-element 13 and the electric motor is energized through closed contacts 29 actuated by the stem of the main valve 36. The cam therefore rotates and, during the first half revolution, the eccentric pin 30 causes the rocker to lift the pilot valve 21 and to move an armature 53 on the end of the stem 33 of the pilot valve into contact with the electromagnet. The stem of the pilot valve is in two parts connected by a telescopic housing enclosing a compression spring. Also during the first half revolution of the cam, notches 23 on the cam cause the contacts 24 to make and break to produce sparking at a spark plug 12 energized by an ignition coil 25 and a condenser 26. Alternatively, an incandescent element and an ignition transformer may be provided. If the pilot burner ignites the electromagnet holds the pilot valve open and the end 31 of the rocker, in raised position and consequently during the second half of the cam revolution the other end 34 of the rocker is depressed to open the main valve 36. The motor contacts 29 also open but the motor continues to run, being energized through the contacts 28 which are kept closed by the cam during its second half revolution. At the end of this second half revolution a notch 27 opens the contacts 28 and the motor stops. The cam is now in its initial position. If the pilot burner fails to ignite the electromagnet is not energized and consequently the pilot valve 21 closes at the end of the first half revolution of the cam lowering the end 31 of the rocker; in consequence the other end 34 of the rocker is unable to open the main valve during the second half revolution of the cam and the contacts 29 remain closed. The motor therefore does not stop at the end of the second half revolution and the cycle repeats. If the thermostat 61 opens, the relay 62 is deenergized and the armature is released from the electromagnet. The valve springs then open the pilot and main valves and tilt the rocker into its initial position with the contacts 29 again closed. The single cam may be replaced by two separate cams on the same shaft.